Thermoelectric water cooler



June 1967 c. F. TER BUSH THERMOELECTRIC WATER COOLER Filed April 1, 1966 J n e j u e m a w a I m w M m m m m w m 2; w 5 7 a .1 f 7 A m n m FIG.4.

INVENTOR Charles F Ter Bush WITNESSES ATTORNEY United States Patent 3,327,485 THERMOELECTRIC WATER COOLER Charles F. Ter Bush, Grove City, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Apr. 1, 1966, Ser. No. 539,526 6 Claims. (Cl. 623) This invention relates to an improvement in thermoelectric water coolers particularly adapted for railroad use.

An object of the invention is to provide an improved structural arrangement of a thermoelectric water cooler to facilitate the removal and replacement of the principal operating components of the water cooler.

The desirability of an arrangement which permits the rapid replacement of the operating components of a water cooler used by railroads is dictated by the fact that train crews may properly refuse to operate a train having an inoperative water cooler.

In accordance with the invention, a thermoelectric water cooler for railroad use is provided which includes: a cabinet; 2. water cooling assembly in the form of an integral package which includes a water cooling tank, a thermoelectric module, and heat sink means of the liquid-vapor filled evaporator-condenser type; means for detachably securing the assembly to the cabinet for removal of the assembly as an integral unit; and means for detachably connecting the thermoelectric module to a source of electrical energization.

The invention will be explained in considerably more detail in connection with the accompanying drawings illustrating a currently preferred embodiment of the invention, and wherein:

FIGURE 1 is a side view of a thermoelectric Water cooler arranged according to the invention, and with the side panel facing the viewer partly-broken;

FIG. 2 is an opposite side view of the unitary assembly comprising the cooling package according to the invention, this view being enlarged relative to FIG. 1;

FIG. 3 is a horizontal sectional view corresponding to one taken along the line III-III of FIG. 2; and

FIG. 4 is a schematic of one circuit arrangement for the water cooler.

The water supply for railroad water coolers is typically a water bottle which is mounted in inverted position on top of the cabinet to drain into a cooling tank inside the cabinet. The cabinet structure shown is rectangular in plan outline and includes a base 12, front and rear panels 14 and 16, respectively, a pair of opposite detachable side panels 18, and top wall 20. The vertical edges of the front and rear panels are formed to provide integral corner posts at the front and rear on each side to stiffen the panels and to accommodate the side panels, and the top wall is downwardly flanged along three edges and secured to the corner posts with fasteners at each corner.

The cooling package assembly is shown in mounted relation on the cabinet in FIG. 1 and as removed from the cabinet in FIG. 2. The assembly includes a platform 26 provided with downturned side flanges 28 secured to side mounting brackets 30 having a front-to-rear length corresponding generally to the front-to-rear dimension of the cabinet. The side brackets are provided with inwardly-offset front and rear ends 32 carrying clip nuts 34 which receive fastening members 36 (FIG. 1) through the cabinet corner posts when the assembly is installed in the cabinet. The upright, cylindrical water cooling tank 38 is "supported from the platform 26 within an outer rectangular sheet metal casing 40 which has its bottom margins secured to the brackets 30.

The thermoelectric module 42 (FIG. 3) is sandwiched between a cold shoe 44 and a boiler or evaporating chamber 46. One face of the shoe 44 is contoured to fit a part of the circular exterior face of the tank 38, and its opposite planar face abuts the cold face of the module. The evaporating chamber in its currently preferred form is a steel block which is drilled vertically to provide a series of upright passages 48, and is drilled horizontally to place the lower ends of the upright passages in communication. The upper ends of the upright passages 48 receive the open ends of condenser tubes 50 (FIG. 2) which are connected to the evaporating chamber in sealed relation. The horizontal passage open end in the block is also plugged so that after the evaporator and condenser are charged with a refrigerant such as R-l2 and the charging entrance closed, the communicating passages and tubes are sealed with respect to atmosphere. In operation the evaporator and condenser serve as the heat sink which dissipates heat from the hot side of the thermoelectric module.

The cooling tank 38 (FIG. 3), the cold shoe 44, the thermoelectric module 42, and the evaporator 46 are held together tightly by means of a band which girdles a part of the circumference of the tank 38 and has its ends secured to tension bolts 52 which pull against opposite ends of a beam plate 54. The beam plate has its center portion fulcurmed on an upright U-shaped member 56 which bears against the exterior face of the evaporator. This type of clamping arrangement which is adaptable to hold the illustrated evaporator, or certain other forms of heat sink, tightly against the thermoelectric module without undue fiexure adversely affecting the interface relationships, is disclosed-and claimed in my copending application Serial No. 465,342, now US; Patent 3,270,513.

During construction of the cooling package assembly, the tank, shoe, module, and heat sink are assembled and clamped by means of the clamping band and then mounted upon the, platform 26. Then the rectangular casing 40 is positioned to encompass the cooling tank and the other interior parts, and a thermal insulating material 58 such as steam expanded styrene insulating beads is poured into the space between the tank and the casing and sealed in at the top by a layer of tar sealer.

The package is also provided with a plate 60 (FIG. 2) carrying an electrical terminal block 62 and an adjustable temperature control member 64, the plate depending from the package. The power source is connected to the terminal block, which in turn is connected to other components, as will be explained later.

The cooling package is installed on the cabinet with the bottle 10, the top wall 20, and the condenser tube guard 68 detached from the cabinet. The cooling package is secured as a unit to the upper portion 66 of the cabinet by simply securing the mounting bracket ends 32 to the corner posts by means of the four fasteners 36 at each side of the cabinet. The rear panel 16 includes a cutout open section 67 above'the level of the platform to accommodate ventilation of the evaporating chamber with ambient air. The condenser tubes 50 project upwardly from the'top face of the evaporating chamber with alternate ones thereof bent to provide a staggered arrangement of the tubes in the portion which projects above the top wall 20 of the cabinet. The condensing tubes preferably are provided with a grid of wires 70 running from tubeto-tube to increase the heat exchange between the tubes and ambient air. After the package is secured, the top wall 20 is installed and secured. The guard 68 is secured to the top wall 20 and the rear panel 16.

The lower interior portion 72 (FIG. 1) of the cabinet accommodates a large voltage dropping resistor 74 which is electrically insulated from the cabinet. A partition wall 76 carrying insulating material 78 directs the heat from the resistor outward and upward to the'outside ambient 3 through ventilation slots 77 in the side panel 18. The ventilation slots cover a large part of the area of the side panels below the cooling package.

The cooling tank 38 (FIG. 2) has a conduit 80 connected to its bottom wall to convey water from the cooling tank 38 to a spigot arrangement 82 recessed in the front panel 14 of the cabinet. The conduit is connected to the spigot through a resilient, self-sealing sleeve connection when the cooling package assembly is installed.

One currently preferred electrical circuit for energization of the module 42 in normal operation will now be described in connection with FIG. 4. The preferred module is of the type designed to operate at 32 volts DC. and 3 to 4 amps. The usual power supply on trains is 64 volts D.C. Thus the resistor 74 is sized to drop the voltage to 32 volts across the module connected in series. The resistor is connected to one side of the 64 volt D.C. line at the terminal block 62, and has its other end connected through line 84 to the module 42 and one side of the temperature control switch 64. The other side of the DC. line is connected to the other terminal of the block 62 and through line 86 to the module; and to resistor '88 in series with switch 64. Thus as shown, the module is in parallel with a shunt circuit including the control switch 64 and the resistor 88. The control switch 64 is responsive to the temperature of the cooling tank 38 and is adjusted to remain open until the tank temperature drops below the set temperature. While the control switch is open the dropping resistor and the module are in series across the line, with the shunt circuit being open. When the set temperature is reached, the control switch 64 closes to place the shunt circuit in parallel with the module. The major part of the current then is carried through the .shunt circuit since the resistance of the resistor '88 is selected to present approximately /5 of the resistance of the module. Accordingly, the module operates to provide substantially reduced cooling when the shunt circuit is closed. The purpose of this arrangement is to prevent rapid heat migration back into the cold shoe from the hot side of the module after the module is deenergized. The small current flow through the module assembly when the shunt circuit is complete is sufiicient to keep the heat from the heat sink from backing up through the cold plate, but is insufficient to cool the cold shoe appreciably further. Such operation might be characterized as idling of the module. Of course as water is drained from the cooling tank, the control switch 64 will open when it senses that the temperature has risen sufficiently above the set point temperature, and the module 42 will again be fully energized.

An alternative and simpler circuit may be used in which the shunt circuit is omitted and the temperature control switch 64 placed in series with both the dropping resistor and module. In this case the switch remains closed until the cooling tank temperature drops to the set point, and it then opens.

It will be understood that the way the heat sink dissipates heat is by vaporizing the liquid refrigerant in the evaporator so that it passes up into the condensing tubes and releases heat to the ambient air during condensation. The condensed refrigerant passes back into the evaporator and is again vaporized while the module remains energized.

A construction according to the invention is advantageous in railroad service in that a spa-re cooling pack- .age may be kept on the train or at nearby repair locations for quick replacement of any package which fails in service. To replace a cooling package, one or both side panels 18 are removed, the bottle is removed, and the tube guard 68 is detached along with the top wall 20. The electrical connections to power at block 62, and to dropping resistor 74 are also disconnected. Then the two fasteners 32 holding each mounting bracket end 32 to a corner post of the cabinet are removed, and the package may be moved backwards and up out of the cabinet as an integral assembly. The reverse procedure is then followed to install the replacement cooling package and other parts to quickly restore the cooler to service.

By using a heat sink of the character described, and disposing the condenser tubes for exposure to ambient air, the requirement for means for creating a forced draft of air is avoided. Hence no provision need be made for a fan motor adapted for use with the electrical power available, or for the provision of means for converting the power.

I claim:

1. In a thermoelectric water cooler of the type adapted to be supplied by a water bottle:

a cabinet;

a unitary cooling assembly including a thermoelectric module sandwiched between a water cooling tank, and heat sink means including a sealed evaporatorcondenser system containing a liquid vapor phase fluid,

means for detachably securing said assembly to said cabinet for removal of said assembly as a unitary assembly, said condenser portion of said system comprising a plurality of tubes projecting up from said evaporator and being located substantially outside of said cabinet, said tubes carrying a grid of wires thereon for promoting heat transfer between said tubes and ambient air about said cabinet; and

circuit means for connecting said thermoelectric module to a source of electrical power.

2. In a cooler according to claim 1:

said cabinet includes frame means supporting a detachable top wall overlying said cooling tank; and

said unitary assembly includes a bottom platform adapted to be detachably secured to said frame means at a level below said top wall to mount said cooling assembly in an upper portion of said cabinet.

3. In a cooler according to claim 2:

said cabinet includes opposite side panels detachably secured to said frame means.

4. In a cooler according to claim 2:

said cabinet includes a rear side panel having an upper open portion for circulation of ambient air about said evaporator.

5. In a cooler according to claim 1:

said cabinet includes a lower interior portion containing voltage dropping resistor means adapted to be connected in said circuit means in series with said thermoelectric module; and

insulated wall means separating said lower interior portion from said upper interior portion containing said cooling assembly.

6. In a cooler according to claim 5:

said circuit means includes means for controlling energization of said module in accordance with said cooling tank temperature, said control means including a shunt circuit in parallel with said thermoelectric module, said shunt circuit including switch means operable to a closed position in response to a fall in temperature of said cooling tank to a preselected low temperature,

and idler resistor means in series with said switch means said shunt circuit being of substantially less resistance than said module to permit said module to operate at a substantially reduced capacity when said switch means is closed.

References Cited UNITED STATES PATENTS 1,581,429 4/1926 Donle 219-441 2,122,650 5/1938 Keene 219-494 2,932,953 4/1960 Becket 623 3,088,289 5/1963 Alex 623 3,250,433 5/1966 Christine 623 WILLIAM J. WYE, Primary Examiner. 

1. IN A THERMOELECTRIC WATER COLLER OF THE TYPE ADAPTED TO BE SUPPLIED BY A WATER BOTTLE; A CABINET; A UNITARY COOLING ASSEMBLY INCLUDING A THERMOELECTRIC MODULE SANDWICHED BETWEEN A WATER COOLING TANK, AND HEAT SINK MEANS INCLUDING A SEALED EVAPORATORCONDENSER SYSTEM CONTAINING A LIQUID VAPOR PHASE FLUID, MEANS FOR DETACHABLY SECURING SAID ASSEMBLY TO SAID CABINET FOR REMOVAL OF SAID ASSEMBLY AS A UNITARY ASSEMBLY, SAID CONDENSER PORTION OF SAID SYSTEM COMPRISING A PLURALITY OF TUBES PROJECTING UP FROM SAID EVAPORATOR AND BEING LOCATED SUBSTANTIALLY OUTSIDE OF SAID CABINET, SAID TUBES CARRYING A GRID OF WIRES THEREON FOR PROMOTING HEAT TRANSFER BETWEEN SAID TUBES AND AMBIENT AIR ABOUT SAID CABINET; AND CIRCUIT MEANS FOR CONNECTING SAID THERMOELECTRIC MODULE TO A SOURCE OF ELECTRICAL POWER. 